The invention relates to a hollow profile, in particular an extruded profile, having at least one laterally protruding flange, in vehicle or aircraft construction, and to a method for the production thereof.
At present, hollow profiles having a flange can only be bent with great difficulty, since the stresses in the flange very rapidly reach their limit and then the hollow profile tears at this point. Hollow profiles of this type also cause difficulties in other types of deformation techniques, for example the internal high-pressure deformation technique. If, in this case, the flange is clamped in the manner of deep-drawing between the deforming-appliance parts, during the expansion by means of internal high pressure hollow-profile material flows away from the flange region into the regions to be expanded, as a result of which tears can easily be produced during the deformation procedure on account of the thinning of the material. This does not in any way produce deformation which is reliable during the process.
A hollow profile of the generic type is disclosed in DE 41 29 329 A1. In this case, a hollow profile is connected to a sheet-metal section by means of a connecting element formed as an expanding-profile body in such a manner that the joint produced as a result can be subjected to a high mechanical load. This connection is relatively complex on account of the use of the additional connecting element because of its production and installation. If, in order to simplify the connection, the expanding-profile body is dispensed with, during deformation of the hollow profile the sheet-metal section is at least displaced in the circumferential direction of the bent sheet-metal end, or the sheet-metal section can even become detached from the hollow profile. As a result, the reliability during the process when the hollow profile is deformed is not ensured.
The present invention is aimed at overcoming one or more of the problems as set forth above.
The invention is based on the object of developing a hollow profile of the generic type to the effect that said hollow profile can be deformed in a simple manner and ensuring the reliability during the process. Furthermore, the intention is to indicate a method for its production.
The invention enables the hollow profile to be manufactured with a flange by a modular design consisting of a flangeless hollow-profile blank and sheet-metal strip, as a result of which the hollow profile can be deformed freely within wide limits. In particular, it is now possible for the deformation which is required for a desired divergence of the hollow profile from a rectilinear extent, for example deformation under bending conditions, to be carried out, in a simple manner, with less outlay on constructional tools and in a reliable manner during the process, solely on the rectilinear, flangeless hollow-profile blank, after which the flange, which is formed by the sheet-metal strip, is only mounted on the hollow-profile blank, in order to form the hollow-profile end form, once the said deformation of the hollow-profile blank has taken place. In order to connect the said flange to the hollow profile likewise in a simple and non-releasable manner and thereby to achieve the required flexural strength of the hollow profile, and also to secure the mounting flange rigidly to the hollow profile in order to effectively install the hollow profile, intimate interlocking between the two joining partnersxe2x80x94the sheet-metal strip and the hollow-profile blank, is necessary. For this purpose, the joining partners are a priori designed with joining elements which can be intermeshed, the final interlocking between the joining elements being achieved by internal high-pressure deformation of the hollow-profile blank. In this process, the material of the blank flows to the contour of the joining element of the sheet-metal strip and positions itself there in an identical form, after which work-hardening under cold conditions takes place. The expansion of the blank caused by internal high pressure is not affected by the flange, since the said flange as a separate component is connected to the blank by another material and not integrally. Therefore, even when the flange is mounted, the reliability during the process is ensured. Also, a certain cross-sectional shaping of the hollow profile can readily take place with reliability during the process by means of internal high-pressure deformation prior to or at the same time as the mounting of the flange, the flange in no way adversely affecting the deformation for the same reasons. Furthermore, the invention makes it possible to provide the flange on the hollow profile in a specific manner, to be precise only in the regions in which it is required for the mounting. Until now, in the case of the known hollow profiles having a flange the flanges had to be partially cut to length and/or milled off, which, because of the additional processing step, is complicated and expensive, and overall requires an unnecessarily large amount of material. In contrast, in addition to a reduced consumption of material and improved protection of resourcesxe2x80x94a not insignificant aspect for the lightweight construction, the hollow profile according to the invention, because of the saving on material, produces a saving on weight and also, at the flangeless locations, additional constructional space which can be used, for example, for an increased cross-sectional enlargement of the hollow profile by means of internal high pressure or for freer designing of those components of the vehicle which are adjacent to the hollow profile.